Night Cooling
Night cooling by ventilation is used to lower the temperature of the thermal mass of the building at night when the outdoor air temperature is substantially below that of the mid-day air temperature. When correctly designed and controlled, this enables the daytime peak temperature to be reduced by up to 3K, even during extended periods of hot weather. Latent cooling does not take place during this process, therefore the technique is not suitable for high humidity climates (above 60% relative humidity).
To accomplish night cooling effectively, ventilation air must be in direct contact with the thermal mass of the building (i.e. there should be no insulated coverings, false ceilings or suspended floors etc.) Good coupling keeps the indoor mid-day temperature below the outdoor temperature, poor coupling keeps it above.